Solution

The VSEPR-predicted shapes of CH
3 OCH
3 , CH
3 CH
2 OH, and CH
3 CH
2 CH
3 are similar, as are their molar masses (46 g/mol, 46 g/mol, and 44 g/mol, respectively), so they will exhibit similar dispersion forces. Since CH
3 CH
2 CH
3 is nonpolar, it may exhibit
only dispersion forces. Because CH
3 OCH
3 is polar, it will also experience dipole-dipole attractions. Finally, CH
3 CH
2 OH has an −OH group, and so it will experience the uniquely strong dipole-dipole attraction known as hydrogen bonding. So the ordering in terms of strength of IMFs, and thus boiling points, is CH
3 CH
2 CH
3 <CH
3 OCH
3 <CH
3 CH
2 OH. The boiling point of propane is −42.1 °C, the boiling point of dimethylether is −24.8 °C, and the boiling point of ethanol is 78.5 °C.

Check your learning

Ethane (CH
3 CH
3 ) has a melting point of −183 °C and a boiling point of −89 °C. Predict the melting and boiling points for methylamine (CH
3 NH
2 ). Explain your reasoning.

Answer:

The melting point and boiling point for methylamine are predicted to be significantly greater than those of ethane. CH
3 CH
3 and CH
3 NH
2 are similar in size and mass, but methylamine possesses an −NH group and therefore may exhibit hydrogen bonding. This greatly increases its IMFs, and therefore its melting and boiling points. It is difficult to predict values, but the known values are a melting point of −93 °C and a boiling point of −6 °C.

Hydrogen bonding and dna

Deoxyribonucleic acid (DNA) is found in every living organism and contains the genetic information that determines the organism’s characteristics, provides the blueprint for making the proteins necessary for life, and serves as a template to pass this information on to the organism’s offspring. A DNA molecule consists of two (anti-)parallel chains of repeating nucleotides, which form its well-known double helical structure, as shown in
[link] .

Two separate DNA molecules form a double-stranded helix in which the molecules are held together via hydrogen bonding. (credit: modification of work by Jerome Walker, Dennis Myts)

Each nucleotide contains a (deoxyribose) sugar bound to a phosphate group on one side, and one of four nitrogenous bases on the other. Two of the bases, cytosine (C) and thymine (T), are single-ringed structures known as pyrimidines. The other two, adenine (A) and guanine (G), are double-ringed structures called purines. These bases form complementary base pairs consisting of one purine and one pyrimidine, with adenine pairing with thymine, and cytosine with guanine. Each base pair is held together by hydrogen bonding. A and T share two hydrogen bonds, C and G share three, and both pairings have a similar shape and structure
[link] .

The geometries of the base molecules result in maximum hydrogen bonding between adenine and thymine (AT) and between guanine and cytosine (GC), so-called “complementary base pairs.”

The cumulative effect of millions of hydrogen bonds effectively holds the two strands of DNA together. Importantly, the two strands of DNA can relatively easily “unzip” down the middle since hydrogen bonds are relatively weak compared to the covalent bonds that hold the atoms of the individual DNA molecules together. This allows both strands to function as a template for replication.

Questions & Answers

Rutherford chose gold was because its extremely malleable. One can stretch gold foil until it is only a few atoms thick in places, which is not possible with aluminum. If the foil were too thick, there would be no transmission of particles at all; the whole point was to demonstrate that most alpha

daniel

wjat does Rutherford mean?

Asali

Ernest Rutherford was the scientist that preformed the experiment.

daniel

although other metals are also present which are more melleable!?so

Lareb

gold

daniel

Join the discussion...

what is a balanced equation 4 trioxonitrate (V)acid and sodium hydroxide?

proved ur Worth: If A is a of trioxonitrate(V)acid,HNO3' of unknown concentration .B is a standard solution of sodium hydroxide containing 4.00g per dm cube of solution.25cm cube portions solution B required an average of 24.00cm cube of solution A for neutralization,using 2 drops of methyl orange.

Marcel

calculate the concentration of solution B in moles per dm cube

Marcel

calculate the concentration of solution A and B in moles per DM cube

Marcel

finally calculate the concentration in g/dm cube of HNO3 in solution A (H=1,N=14,O=16,Na=23)

Marcel

calculate the standard enthalpy of formation for propane(C3H8) from the following data;
1), C3H8+5O2->3CO2+4H2O; -222.0kJ/mol
2), C+O2->CO2;-395.5kJ/mol
3),H2+O->H2O; 285.8kJ/mol

many ways ,but one of them is when the atom becomes heated to a certain temperature the surface electron becomes too energetic and leaves the atom because the attraction between the nucleus and the electron becomes overpowered by the energetic eletron

Taking Sodium as example..... it carries a positive charge which means it is positively charged.....when it gains an electron, it is reduced cuz an electron is negatively charged.....also when an atom looses an electron, it becomes positively charged and when it gains, it becomes negatively charged.

Nuru

typically, ionization is the process where an atom looses or gains electron(s) to form ion(s) either a positively or negatively

can you explain what you are needing it now better than maybe I'm just not interpreting it what you're needing to know

Alex

cool nitrogen down to around negative 270 °F and it will be solid. now they are both solid

daniel

they are different elements and dats how they are pal.....check the periodic table

Nuru

Nitrogen is a diatomic molecule with relatively weak van de waals forces between the molecules. These forces are overcome when the solid melts or liquid evaporates. Phosphorus forms larger molecules consisting of four phosphorus atoms in a tetradedral shape. The intermolecular forces are stronger